CN100358254C

CN100358254C - Optimization method for power protection in wireless communication system

Info

Publication number: CN100358254C
Application number: CNB2004100581896A
Authority: CN
Inventors: 孟庆锋
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2004-08-13
Filing date: 2004-08-13
Publication date: 2007-12-26
Anticipated expiration: 2024-08-13
Also published as: CN1734964A

Abstract

The present invention discloses an optimization method for power protection in a wireless communication system. The optimization method has the following steps: threshold power is quantized into a threshold power parameter; a range of statistical power exceeding the threshold power is quantized into a range of the threshold power parameter by a prearranged power step, and each power step and a real power value corresponding to each power step are stored in a quantification table of the statistical power; a power range needing to be attenuated is quantized into a range of a fixed point quantization value of an attenuation factor, and the fixed point quantization value of each attenuation factor is stored in a quantification table of the attenuation factor; a statistical power value actually measured is quantized according to the quantization table of the statistical power, and a corresponding power step is obtained; the fixed point quantization value of the attenuation factor in the quantification table of the attenuation factor is looked up according to the difference value of the power step and the threshold power parameter, input signals are respectively multiplied by the fixed point quantization value of the attenuation factor, and multiplication results are rightward shifted for Z bits to carry out power attenuation, wherein the z is the quantification bit width of the attenuation factor.

Description

The optimization method of power protection in wireless communication system

Technical field

The present invention relates to a kind of method of power protection, relate in particular to a kind of optimization method in power protection in wireless communication system.

Background technology

At wireless base station subsystem (comprising GSM base station and cdma base station) operation irregularity; under the situation as Base-Band Processing logical miss, parameter configuration mistake etc.; can produce the situation that sends high-power signal in the short time to base station radio frequency module; for fear of high-power signal radio-frequency module is caused damage; often need use the power resist technology; the power resist technology can make the power that is input to radio-frequency module be no more than the maximum of design; thereby radio-frequency module is played the effect of protection, and general power control all realizes by FPGA (programmable logic device).

Figure 1 shows that the schematic diagram of power guard method implementation procedure; the user disposes a threshold power; the configuration of threshold power value is generally than the high 1dB～2dB of radio-frequency module maximal input; system is in radio-frequency module input real-time statistics transmitting power; the user adds up duration according to the time span configuration of the high-power impact signal that radio-frequency module in the system can be stood; for convenience of calculation; generally get 2 integral number power; according to the difference between current transmit power that counts and the user configured threshold power; whether decision needs to reduce the power of input data and the size that needs reduce the input data power; the input data power of Jiang Diing calculates power adjusting factor as required, according to power adjusting factor the input data power is adjusted.The input data here refer generally to I, the Q data of base band or intermediate frequency.

Figure 2 shows that the schematic flow sheet that the power guard method realizes in the prior art, the data of establishing input are I, Q (I, Q represent the two paths of signals of quadrature each other), and user configured threshold power is P _Threshold, power statistic length is N, then adds up power

P_{statistics} = \frac{1}{N} Σ_{i = 0}^{N - 1} (I_{i}^{2} + Q_{i}^{2}),

Wherein i represents i sampling point.Work as P _Statistics＞P _Threshold, then expression should reduce input signal power, and it is (P that power reduces size _Statistics-P _Threshold), correspond to input signal amplitude resize ratio K and be

The amount that amplitude resize ratio K representative input data need decay, thus amplitude resize ratio K be one greater than 0, and less than 1 number, and that FPGA realizes for the multiplication of decimal is inconvenient, therefore needs this decimal is fixed a point to quantize, and is about to this decimal and amplifies 2 ^m, become an integer, with the input data and this integer multiply after again divided by 2 ^mGet final product.If amplitude resize ratio K m bit quantization, then I, the Q data with input multiply by respectively

\sqrt{(\frac{P_{statistics}}{P_{threshold}} - 1)} \times 2^{m},

When K＜1, the output result that will multiply each other is divided by 2 ^mCan realize the power adjustment; When 2 ^h＜K＜2 ^H+1(h is meant that the power P statistics that comes out is 2 of threshold power Pthreshold ^hDoubly, h is a positive integer) time, the output result that will multiply each other is divided by 2 ^(m+h), can realize the power adjustment.Concrete formulate is as follows:

Owing to relate to division arithmetic, extracting operation and the multiplying of bit wide broad in the above-mentioned prior art, therefore cause it to realize complex structure, when utilizing FPGA (programmable logic device) to realize, can cause consuming a large amount of logical resources, thereby cause the FPGA difficult wiring, increase designer's workload, finally caused the increase of product cost.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of optimization method of power protection in wireless communication system.

For solving the problems of the technologies described above, the invention provides a kind of optimization method of power protection in wireless communication system, realize by programmable logic device, comprise step:

1) threshold power is quantified as the threshold power parameter;

6) will add up the scope that power exceeds threshold power and be quantified as the threshold power parameter area with the predetermined electric power step, the actual power value that each power step is corresponding with it deposits in the statistics power quantization table;

7) power bracket that will need to decay is quantified as decay factor fixed point quantized value scope, and each decay factor fixed point quantized value is deposited in the decay factor quantization table;

8) according to statistics power quantization table the statistics performance number that actual measurement goes out is quantized, draw its corresponding power step;

9) according to the difference of power step and threshold power parameter, in the decay factor quantization table, search decay factor fixed point quantized value, input signal is multiplied each other with decay factor fixed point quantized value respectively, z bit again moves to right multiplied result, to carry out the decay of power, wherein z is the quantification bit wide of decay factor.

Threshold power in the described step 1) turns to the threshold power parameter according to power control precision required amount.

The power bracket of the needs decay in the described step 3) turns to decay factor according to power control precision required amount and quantizes the step scope.

Input data in the described step 5) are I, the Q data of quadrature.

Described statistics power quantization table is stored in the memory of programmable logic device.

Described decay factor quantization table is stored in the memory of programmable logic device.

Compared with prior art, the invention has the beneficial effects as follows:

The present invention will add up the power quantization table and decay factor quantization table calculated in advance is come out, and finishes the calculating of the attenuation of power by table lookup operation, thereby has avoided the complex mathematical computing, has saved a large amount of logical resources.Because statistics power quantization table is consistent with the power control precision that decay factor quantizes, the realization precision of whole power protection algorithm is effectively guaranteed.

Description of drawings

Fig. 1 is the schematic diagram of power guard method implementation procedure;

Fig. 2 is the realization flow schematic diagram of power guard method in the prior art;

Fig. 3 is the realization flow schematic diagram of power protection optimization method of the present invention.

Embodiment

Power protection optimization method of the present invention is realized by FPGA (programmable logic device).As shown in Figure 3, the concrete steps of power protection optimization method of the present invention are as follows:

Step 1: threshold power is quantified as the threshold power parameter;

The configuration of threshold power has certain limit, supposes that the threshold power scope is XdB, because the power of digital system generally uses dBFS to weigh (dBFS is meant the power with respect to ull-scale value), and the power of ull-scale value corresponding 0dBFS, threshold power P like this _ThresholdScope be (0dBFS～XdBFS).If the power control precision requires to be mdB, then the span of user's threshold power parameter s that need dispose is for (0～r), r is that X/m rounds.

Step 2: will add up the scope that power exceeds threshold power and be quantified as power step scope, the actual power value that each power step is corresponding with it deposits in the statistics power quantization table;

If user configured statistics duration is N, then add up power

P_{statistics} = \frac{1}{N} Σ_{i = 0}^{N - 1} P_{i},

Wherein Pi is the performance number of single sampling point.Because the scope of user configured threshold power is 0dBFS～XdBFS, therefore under the unusual situation of wireless base station subsystem work, the scope that statistics power maximum possible exceeds threshold power is 0dBFS～XdBFS, if the power control precision requires to be mdB, then add up the scope that power may exceed threshold power and can be quantified as 0～r, r is that X/m rounds, for the power P of each power step correspondence _j(span of j is 0～r) to=j * m (dB), the power step is meant each step value that power is adjusted, the bit wide of supposing the power ull-scale value is n (representing the power maximum with the binary data of a n bit), and its corresponding actual power can be according to formula

{Power}_{j} = 10^{\frac{P_{j}}{10}} \times (2^{n} - 1)

Calculate, because P _jBe given value, thereby can obtain a complete power quantization table, the size of table is r+1.The power step is numbered 0～r.Be that corresponding actual power value with each power step numbering in statistics performance number and the power quantization table compares and obtains adding up the corresponding power step of performance number and number during use.The power quantization table is stored in the memory of FPGA inside, and its example is as follows:

Step 3: the power bracket that will need to decay is quantified as decay factor quantification step scope, each decay factor is quantized the step decay factor fixed point quantized value corresponding with it deposit in the decay factor quantization table;

Decay factor is used for representing the amount that the data imported need decay, thus decay factor be one greater than 0, and less than 1 number, and that FPGA realizes for the multiplication of decimal is inconvenient, therefore needs this decimal is fixed a point to quantize, and is about to this decimal and amplifies 2 ^z, become an integer, with the input data and this integer multiply after again divided by 2 ^zGet final product.

The scope that surpasses threshold power according to the statistics power maximum possible of preceding surface analysis is 0dBFS～XdBFS, and therefore needing the maximum magnitude of decay is 0dB～XdB, and the precision of establishing power control is mdB, and then the scope of decay factor look-up table is 0～r, and r is that X/m rounds.If the quantification bit wide of decay factor is the z bit, the decay factor quantization table is stored in the internal storage of FPGA, and its form is as follows:

Step 4: according to statistics power quantization table the statistics performance number that actual measurement goes out is quantized, draw its corresponding power step;

With the performance number P that comes out _StatisticsCompare successively with the performance number in the statistics power quantization table of step 2, when

10^{- \frac{(c + 1) \times m}{10}} \times (2^{n} - 1) < P_{statistics} \leq 10^{- \frac{c \times m}{10}} \times (2^{n} - 1)

The time, then the power step of this statistics performance number correspondence is numbered c; If user configured threshold power parameter is that (span of s is 0～r) to s, can obtain the size that whether will decay and decay by a simple subtraction (s-c) like this.When s＞=c, expression statistics performance number is more than or equal to the threshold power value, and (s-c) * mdB need decay in following N sampling point; When s＜c, expression statistics performance number need not decayed in following N sampling point less than the threshold power value.

Step 5: according to the difference of power step and threshold power parameter, in the decay factor quantization table, search corresponding decay factor fixed point quantized value, the data of a next N sampling point are multiplied each other with the decay factor fixed point quantized value that obtains of tabling look-up respectively, the z bit that again multiplied result moved to right can realize adding up the decay of power.

Look into the process of decay factor table: at first judge the size of s and c, s is the threshold power parameter, and c is the power step numbering of the power correspondence that comes out, and when s＞=c, index=s-c then thereby check in the decay factor value is

10^{- \frac{index \times m}{20}} \times (2^{z} - 1);

When s＜c, index is fixed as 0, and the decay factor value is fixed as 2 like this ^z-1.

The data of next N sampling point of input power are multiplied each other with the decay factor value that obtains of tabling look-up respectively, the I, the Q data that are about to next N sampling point of input power multiply each other with the decay factor value that obtains of tabling look-up respectively, the z bit that again multiplied result moved to right can be realized the decay of power.

The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims

1, a kind of optimization method of power protection in wireless communication system is realized by programmable logic device, it is characterized in that, comprises step:

1) threshold power is quantified as the threshold power parameter;

2) will add up the scope that power exceeds threshold power and be quantified as the threshold power parameter area with the predetermined electric power step, the actual power value that each power step is corresponding with it deposits in the statistics power quantization table;

3) power bracket that will need to decay is quantified as decay factor fixed point quantized value scope, and each decay factor fixed point quantized value is deposited in the decay factor quantization table;

4) according to statistics power quantization table the statistics performance number that actual measurement goes out is quantized, draw its corresponding power step;

5) according to the difference of power step and threshold power parameter, in the decay factor quantization table, search decay factor fixed point quantized value, input signal is multiplied each other with decay factor fixed point quantized value respectively, z bit again moves to right multiplied result, to carry out the decay of power, wherein z is the quantification bit wide of decay factor.

2, the optimization method of power protection in wireless communication system according to claim 1 is characterized in that: the threshold power in the described step 1) turns to the threshold power parameter according to power control precision required amount.

3, the optimization method of power protection in wireless communication system according to claim 1 is characterized in that: the power bracket of the needs decay in the described step 3) turns to decay factor according to power control precision required amount and quantizes the step scope.

4, the optimization method of power protection in wireless communication system according to claim 1 is characterized in that: the input data in the described step 5) are I, the Q data of quadrature.

5, the optimization method of power protection in wireless communication system according to claim 1 is characterized in that: described statistics power quantization table is stored in the memory of programmable logic device.

6, the optimization method of power protection in wireless communication system according to claim 1 is characterized in that: described decay factor quantization table is stored in the memory of programmable logic device.